Fluorescent probes are typically used for qualitative and/or quantitative titrations in various fields such as immunology, molecular biology, medical diagnostic . . . . An ideal condition for a compound to be used as fluorescent probe, and thus allow the titration of a target analyte, is to display dual emission properties varying depending upon the conditions (presence or not of the analyte, pH . . . ). Such compounds allow, for example, ratiometric titrations leading to the determination of the analyte concentration, whatever the fluorescent probe concentration.
In the field of luminescent devices, the use of compounds having dual emission properties can lead to the production of polychromatic fluorescence such as white light, without requiring several polychromatic emitters.
Only few systems using a single molecule are known to exhibit dual emission.
However, dual emission, and more particularly white light emission, from a single molecule is an important chemical target because of the possibility of innovative applications to new classes of displays and light sources, such as low-cost, large-area flat-panel displays. Most of the white organic light-emitting devices (WOLEDs) reported so far relied on the use of a combination of several organic components that emit different colors of light (e.g. red/blue/green luminophores) to cover the visible range from 400 to 700 nm.
Therefore, the search for new molecules that can exhibit dual emission properties, and more particularly white light emission properties, is of obvious interest and importance.